An animal model is proposed for the objective quantification of vomiting induced by anticancer agents, and for testing new classes of antiemetics against these drugs. Recording of intrathoracic pressure via a jugular venous catheter provides a continuous monitor of emetic activity in unrestrained awake cats. Emesis produces a unique and unambiguous sequence of pressure variations in the thoracic cavity which distinguishes two basic emetic components, namely retching and expulsion. Cumulative vomiting episodes plotted against time establishes a characteristic emetic response profile for each drug. Three anticancer agents (BCNU, mechlorethamine and cis-Pt) will be defined in this way, as will selected standard emetic drugs (deslanoside, apomorphine and veratrum). The antiemetic action of certain psychoactive compounds, i.e., nabilone (a synthetic cannabinoid), three narcotics (morphine, fentanyl and methadone) a prochlorperazine will be assessed on the basis of their effect on the standard emetic response profile of each of the emetic agents. Specific end-points for determining antiemetic activity include latency, severity and time course. Development of tolerance to the various agents after repeated exposure will be evaluated. Additionally, neurophysiological experiments are devised for elucidating locus and mechanism of drug action if time permits.